Smiling broadly, Benedict raised his arms outstretched in his penultimate Angelus blessing before leaving the papacy. A huge banner in the square read: "We love you."

The blessing, which takes place at midday on Sunday, is one of the most cherished traditions of the Catholic church, and this was one of Benedict's last opportunities to connect with the masses.

His voice was strong and clear as he looked into hazy sunshine over the square and addressed at least 50,000 pilgrims in Italian, English, French, German, Polish and Spanish.

Benedict made no direct reference to his decision to step down, but in his Spanish comments he asked the crowd to "continue praying for me and for the next pope".

He thanked the crowd for their "affection and spiritual closeness", and gave particular thanks to the "beloved inhabitants of the city of Rome", a possible hint at the title he will take after retirement. The Vatican has suggested he may be called the emeritus bishop of Rome.

A sign in the crowd at the Vatican. Photograph: Alessandra Benedetti/Corbis

The Angelus blessing normally attracts a few thousand pilgrims and tourists, but city officials prepared for a crush of people seeking to witness a moment of history.

"We wanted to wish him well," said Amy Champion, a tourist from Wales. "It takes a lot of guts to take the job and even more guts ... to quit."

Rome put on extra buses and underground trains to help deal with the crowds, and offered free shuttle vans for elderly and disabled people.

After Sunday evening the pope will be out of the public eye for a week. A meditation service at the Vatican marks the beginning of the traditional Lenten period of reflection and prayer.

While cardinals elect his successor next month in a conclave in the Sistine Chapel, Benedict will be in retreat at the Holy See's summer estate in the hills south-east of Rome. After several weeks he is expected to move into a monastery being refurbished for him behind the Vatican City walls, where he will lead a largely cloistered life.

The Vatican has not announced a date for the start of the conclave, but said on Saturday that it might start sooner than 15 March, the earliest date it can be launched under current rules. Benedict would have to sign off on any earlier date, an act that would be one of the last of his nearly eight-year papacy.

The first cardinals have started arriving in Rome to begin a period of intense politicking to decide who are the leading candidates to be the next pope. The Guinea-born archbishop Robert Sarah, a cardinal who leads the Vatican's charity office, told reporters when he arrived that the churchmen should select their new leader with "serenity and trust".